I also love carapacians! Was this close to naming myself sovereignSlayer on the forum as an homage to Jack Noir lol.

Speaking of Jack, and building on what you're saying, possibly among my least favorite writing choices in Homestuck was how Bec Noir/the beta kids' Jack was basically dropped as an antagonist. It feels as though most of the early acts are hyping him up as the ultimate villain, one that cannot be stopped by any conventional means, only to have him be followed by PM for three years, be punched out by her, and eventually be unceremoniously killed off in a blink-and-you'll-miss-it scene in a "Flash" animation in Homestuck^2. Spades Slick also got the short end of the stick, too; even if he was a villainous, treacherous mobster asshole, he was still an entertaining protagonist of the Intermissions and deserved more than being blown up. (Don't have much to say on Union Jack or the cherub session's Jack, though...)

That's not to mention all the other interesting carapacians, though--a particular favorite is, no surprise, WV for his antics and heroism, though it seems to me like he really was somewhat infantilized by the characters and to a certain extent, the narrative, especially in act 6. PM's dedication to her duties through thick and thin are admirable, whether those duties are delivering a parcel to Egbert or tracking down and defeating Bec Noir. AR was a fun character and deserved more time in the limelight, Snowman was a great femme fatale foil to Slick, and the Kings must have been formidable antagonists to the trolls in particular (Rex Duodecim Angelus, anyone?). That's saying nothing of the other members of the Midnight Crew...but I digress, this is getting way too long.

(That said, I don't have as much to say on the Leprechauns. Their gimmicks are interesting but I don't think of them as much as the carapacians. Not that they're not good or fun characters though!)

The Black motif is also a really good one, honestly Bilious is one of my favorite Homestuck songs specifically because of its inclusion!